Heat 2 tablespoons of the oil in a medium saute pan over medium-high heat. Add the onion and cook until soft, 3 to 4 minutes. Add the garlic and jalapeños and cook for 1 minute. Remove from the heat and set aside to cool slightly.

In a large mixing bowl, whisk together the sour cream, horseradish, mustard, and onion mixture until combined. Pick over the crabmeat to remove any bits of shell. Add the crab and the flour to the bowl and gently fold to combine; season with salt and pepper. Refrigerate, covered, for 1 hour and up to 24 hours.

Divide the chilled crab mixture into 8 patties about 1/2 inch thick. Dredge each cake in the cornmeal and tap off any excess.

Heat the remaining 4 tablespoons olive oil in a large nonstick saute pan over high heat and fry the cakes until crusty and lightly golden brown, about 3 minutes on each side.

Place 2 crab cakes on each of 4 dinner plates and top each cake with mango-green onion relish and red pepper sauce. Garnish with chives. Serves 4.

Mango-Green Onion Relish:

2 ripe mangoes, peeled, pitted, and diced

2 green onions, white and green parts, thinly sliced

1 serrano chile, thinly sliced

2 tablespoons fresh lime juice

1 tablespoon honey

2 tablespoons olive oil

Kosher salt and freshly ground black pepper

Combine the mangoes, green onions, serrano chile, lime juice, honey, and oil in a medium bowl and season with salt and pepper. Let the relish sit at room temperature for at least 15 minutes before serving to allow the flavors to meld. This can be made up to 24 hours in advance and refrigerated. Bring to room temperature before serving. Makes about 1 1/2 cups.

Smoked Red Pepper Sauce:

4 red bell peppers, roasted, peeled, seeded, and chopped

1/2 small red onion, coarsely chopped

4 cloves roasted garlic, peeled

1/4 cup red wine vinegar

1 tablespoon honey

1 tablespoon Dijon mustard

1 tablespoon chipotle chile puree

Kosher salt and freshly ground black pepper

1/2 cup canola oil

Combine the red peppers, onion, garlic, vinegar, honey, mustard, and chipotle puree in a blender, season with salt and pepper, and blend until smooth. With the motor running, slowly add the oil and blend until emulsified. Strain the sauce into a bowl. This sauce can be made 1 day in advance and refrigerated. Makes about 2 1/2 cups.